Lateral IGBT in thin SOI for high voltage, high speed power IC

A high voltage LIGBT built in ultra-thin silicon-on-insulator (SOI) with a linearly graded doping profile is reported. The highest breakdown voltage of 720 V was measured for an LIGBT built in 0.5 /spl mu/m SOI with a 4 /spl mu/m buried oxide. A forward voltage drop of 6 V at 100 Acm/sup -2/ and a turn-off time of 140 ns have been achieved in the same device. Device forward voltage drop is very sensitive to the SOI thickness due to the recombination of carriers at the two silicon-silicon dioxide interfaces. An SOI thickness of 0.5 /spl mu/m and an n-buffer doped to 10/sup 18/ cm/sup -3/ have been found to be a reasonable trade-off between the breakdown voltage and the forward voltage drop.